Abstract: A blank and method for using the same wherein the blank for conversion to a stencil by spark erosion through a stencil layer to a conductive face is arranged so that the layer and face do not have to be peeled apart and chemical and physical interaction between them is avoided, by bonding them only close to one edge of the blank. To prevent shrinkage of the layer to be perforated, a supporting backing is attached thereto to be peeled away before perforation. The conductive face on a backing sheet can be detached along a perforated line close to said edge. A spine that remains attached to the perforated layer facilitates mounting the stencil in a machine.

Abstract: A drive transmitting device is disclosed which may be preset and will subsequently become locked if sudden or gradual rotation forces are applied, the device comprising a first member at least part of which is inside a second member, a rotation of one of the members in either direction about an axis of rotation causing a rotation of the other member about the axis. There are rollers around the axis which co-operate with wedging surfaces in the device to prevent a rotation of the said one of the members from its preset position about the axis as a result of a rotation of the said other of the members in either direction about the axis, the rollers being arranged in respective pairs around the axis, the number of such pairs being more than two. The forces required to restrain rotation are shared substantially equally between respective rollers of the pairs.

Abstract: Aluminium or aluminium alloy is electrolytically grained using alternating current and an aqueous electrolyte comprising specified amounts of hydrochloric acid and a monocarboxylic acid containing from 1 to 4 carbon atoms, preferably acetic acid. The grained aluminium or alloy may be coated with a light sensitive layer to form a light sensitive plate for use in the production of lithographic printing plates by photomechanical techniques.

Abstract: There is disclosed safety apparatus for firing equipment. The apparatus includes an electrically readable memory for storing a set of values which indicate directions of firing which are safe as regards where the equipment is mounted and means for providing from indications of actual direction, an inhibition of firing at such directions which are unsafe as regards where the equipment is mounted.

Abstract: The invention provides a method of, and apparatus for, producing a layer of antifriction metal on a metallic surface. The method involves using a die having a recess surrounded by a thin rim; the recess is filled with molten antifriction metal which is allowed to solidify, and thereafter the structure obtained is machined to remove unwanted parts of the die.

Abstract: A radiation sensitive composition comprises a quaternary ammonium salt and a chemical sensitiser of the formula ##STR1## wherein R.sup.21 is aryl, arylakenyl or arylalkyl, R.sup.22 is aryl, alkyl, arylalkenyl, arylalkyl, carboxylic acid or salt, or hydrogen and X is carboxylic acid or salt. The quaternary ammonium salt is of the type which will accept at least one electron on exposure to radiation to form a substance capable of causing metal to be deposited onto said substance from an electroless plating solution in contact with said substance and comprising a salt of said metal and a reducing agent. A radiation sensitive plate comprises a metallic substrate coated with a radiation sensitive layer comprising a quaternary ammonium salt. The layer may be formed of the above composition.

Abstract: A light sensitive material suitable for coating onto a support to produce a light sensitive plate for use in, for example, the manufacture of a printing plate comprises groups of the formula: ##STR1## attached to carbon atoms of a polymer, wherein --Z-- is --o-- or ##STR2## or ##STR3## wherein R.sub.5 represents a hydrogen atom or an alkyl group; R is an aromatic radical; a is zero or unity; R.sub.1, R.sub.2 and R.sub.3 are hydrogen atoms, halogen atoms, cyano groups, or specified aliphatic or aromatic groups; X is a deactivating group; R.sub.4 is a hydrogen atom, a carboxyl group, a cyano group or a specified aliphatic or aromatic group; and Ph is a phenyl group. The material may be produced by reacting a polymer containing epoxide groups, hydroxyl groups, or primary and/or secondary amino groups with the halosulphonyl group of a compound having the formula: ##STR4## wherein R, R.sub.1, R.sub.2 R.sub.3, and a having the above meanings, wherein X has the above meaning or is a halosulphonyl group and R.sub.

Abstract: A composition for improving the ink receptivity of lithographic printing images comprises an organic solvent liquid capable of softening the surface of the printing image and a film forming alkali-resistant oleophilic material such as a liquid hydrocarbon solution of a normally solid hydrocarbon or fat. The composition is for use in the case where the printing image is formed by alkaline development of an image-wise exposed radiation sensitive coating such as a phenol formaldehyde resin in admixture with a sensitiser. The composition may be applied before exposure to form an alkali resistant oleophilic layer on the radiation sensitive coating or it may be applied after image-wise exposure but before alkali development.

Abstract: An electronic franking machine, for example a postal franking machine, has a digital electronic input register, for storing a selected franking value fed in for use in the next franking operation of the machine, and a digital electronic total register which accumulates an indication of the total of the respective franking values used for such operations of the machine since this register was last reset. The machine also has an electrically adjustable printing device, for printing the selected franking value in each franking operation. The printing device is housed in a relatively massive stationary unit of the machine, and the electronic registers and associated circuitry are housed in a relatively light portable unit that is readily separable from the stationary unit to facilitate resetting by a remote authority.

Abstract: A gear box serving as a transmission coupling between nominally co-axial driving and driven shafts with a gear train within a casing of the gear box coupled to these shafts by flexible couplings that are disposed within the casing about the centers of bearings on which the casing is mounted.

Abstract: An optical image splitting apparatus is provided in which an image splitting surface capable of splitting an incident beam into first and second beams by transmission and reflection respectively is so arranged in relation to an uneven number of reflection surfaces that the two beams are reflected through respective paths in the apparatus and leave the apparatus in the same general direction. One of the reflection surfaces is common to the two paths and is deflectable to deflect the two paths in opposite angular directions in order to adjust the distance between the centers of the images formed from the two beams. The apparatus may include a device for blanking out one or other of the beams.

Abstract: In addition to having two lithographic layers of complementary lithographic character, an electrically inscribable lithographic printing blank may be provided with a solid but solvent-removable protective surface layer serving to inhibit spurious abrasion of the underlying layer during inscription of the blank and prior handling and storage. To prepare a printing plate from the blank, an electric current is passed between the blank and an electrical stylus so as to inscribe through the protective layer and immediately underlying layer and expose the bottom layer locally, whereafter the protective layer is removed by treatment with solvent to expose the surface of the underlying layer.

Abstract: The amount of water present on a lithographic printing plate during printing is determined by measuring the amount of water present on a surface which is other than that of the printing plate but which carries an amount of water related to the amount of water present on the printing plate. The surface upon which the measurement is made may be the surface of a control pad mounted on the printing roller in the gap between opposite ends of the printing plate, the surface of one of the rollers of the damp train applying water to the printing plate, or the surface of an auxiliary roller contacting one of the rollers of the damp train applying water to the printing plate. The amount of water subsequently applied to the printing plate may be regulated in dependence upon the amount of water determined as being already present on the printing plate.

Abstract: A desensitizing composition comprises an aqueous solution comprising (i) a polymer containing structural units derived from acrylamide and from 1% by weight to 25% by weight of structural units containing carboxyl groups and (ii) desensitizing acidic material in an amount such that the pH of the solution is less than 5.5. The carboxyl group containing structural units may be derived from acrylic acid and/or an acrylic acid salt and the desensitizing acidic material may be phosphoric acid. The composition may be used as a substitute for gum arabic solution in lithographic plate making processes and lithographic printing processes.

Abstract: A machine for processing image-wise exposed light sensitive plates comprises processing rollers for agitating developer liquid in contact with the plate as the plate passes through the machine. The plate is urged into contact with the rollers by a plate member which is preferably adjustable and provided with recesses and preferably the developer applied to the plate is filtered developer and is applied by spraying. After developer has been removed, the plate is urged into contact with a roller, dipped in desensitizing solution, by means of, for example, a preferably adjustable second plate member. The desensitized developed plate is then dried before leaving the machine.

Abstract: A rotary printing machine including an impression cylinder which has at least two grippers for gripping the forward edge of a sheet of paper for drawing the paper onto the same at each appropriate instant in each cycle of operation of the machine, the grippers being movable circumferentially of the impression cylinder and retainable in a different position which is stationary relative to the impression cylinder, to vary the relative position of the sheet of paper on the cylinder while the cylinder is rotating.

Abstract: A flexible, cantilevered, gear wheel support, comprising a flexible pin mounted at one end in a rotating carrier and carrying at the other end a gear wheel the axis of which, when the pin flexes, remains parallel to the position of this axis in the pin unflexed condition; the pin between its mounting on the carrier and its part that carries the gear wheel presenting a greater resistance to bending in planes radial of the rotational path of the carrier than it presents to bending in planes tangential to this path.

Abstract: A device for use in producing a scanning beam of radiation comprises a rotor member carrying two optical wave guides arranged so as to direct light along the rotary axis of the rotor member, then radially outwardly to pass from one wave guide to the other, then radially inwardly and finally along the said rotary axis again.When the device is adapted for investigating liquid samples, a turntable, carrying a number of vials containing liquid samples at spaced locations around its periphery, is rotated in indexing fashion and, during each dwell period of the turntable, the rotor member is rotated so that the circularly scanning beam of light leaving the first mentioned wave guide scans each of the vials in turn at least once.

Abstract: A flexible, cantilevered, gear wheel support, comprising a flexible spindle united at one end with a carrier and at the other end with a gear wheel support sleeve by means of welds effected by electron beam welding.

Abstract: In an offset lithographic printing machine a recess is provided in the offset blanket in a position such that when the recess is at the nip between the blanket cylinder and the printing plate cylinder the recess is in registry with a part of the non-printing area of the printing plate. The amount of water on that part of the non-printing area is then determined as, for example, a function of the amount of radiation reflected by that part.